1. Field of the Invention
The present invention relates to prosthetic implants and, more particularly, to prostheses for human knee joints that are implantable by means of arthroscopic as well as open surgical techniques.
2. Description of Related Art
It is common to provide implants to resurface worn articular surfaces of knees. Many of the prior art prostheses require large incisions to gain adequate access to the joint space to perform the surgery and the removal of a great deal of bone from the femur and tibia in order to accommodate the implant, thereby causing large amounts of surgical trauma to the patients and reducing the amount of bone available in the event that revision surgery is required. In addition, the removal of too much bone may lead to failure of the implanted prosthesis due to subsidence of the implant into the underlying bone necessitating revision surgery to replace the failed implants.
Bone cement is typically used to secure implant components. Misalignment of components may occur when bone cement is placed on the prepared bone surface before the components are implanted into position. When a component is implanted into bone cement which has been placed on the prepared bone surface, bone cement may escape from between the bone and the edges of the implant. When bone cement is injected into a portal located on a side wall of an implant, bone cement may leak from the portal into the joint space. If left in the joint space, such excess or leaked bone cement may cause irritation. On the other hand, inadequate amounts of bone cement may result in inadequate fixation resulting in the loosening of the implant.